1. Field of the Invention
The present invention relates to a liquid droplet ejecting head having nozzles that eject droplets, pressure chambers that are communicated with the nozzles and are filled with a liquid, a diaphragm that comprises a portion of the pressure chambers, a liquid pool chamber that pools liquid supplied through liquid channels to the pressure chambers, and piezoelectric elements that displace the diaphragm. The present invention also relates to a liquid droplet ejecting device equipped with this liquid droplet ejecting head.
2. Description of the Related Art
Conventionally, inkjet recording devices are known in which ink droplets are selectively ejected from multiple nozzles of an inkjet recording head (hereafter, there are cases where this is simply referred to as “recording head”) which acts as a liquid droplet ejecting device. Such devices print text and images on a recording medium such as recording paper.
In these inkjet recording devices, various systems are used in the recording head such as piezoelectric systems and thermal systems. In, for example, the case of a piezoelectric system, a piezoelectric element 206 (i.e., an actuator that converts electric energy into mechanical energy) is provided in a pressure chamber 204 to which ink 200 is supplied through an ink pool chamber 202 from an ink tank (refer to FIGS. 24 and 25). The piezoelectric element 206 is configured so as to flex deform in a concave shape and make the volume of the pressure chamber 204 decrease and pressurize the ink 200 inside, thereby making the ink eject as an ink droplet 200A from a nozzle 208 communicated with the pressure chamber 204.
With inkjet recording heads of this kind of configuration, there has been a demand in recent years for recording heads that can provide high-resolution printing while maintaining compactness and low cost. In order to answer this need, it is necessary to set the nozzles such as to provide a highly dense arrangement. Nonetheless, as shown in the drawings, current recording heads have the ink pool chamber 202 provided next to the nozzles 208 (i.e., between each of the nozzles 208) so there has also been a limit to the degree to which the nozzles 208 can be arranged in highly dense formations.
Moreover, a drive IC that applies voltage to predetermined piezoelectric elements is provided in the inkjet recording head. As shown in FIG. 26, this is conventionally mounted with a flexible print circuit (FPC) 210. That is, bumps 212 formed at the FPC 210 are joined to the metallic electrode surface of the upper surface of the piezoelectric element 206 provided on a diaphragm 214. At this stage, the piezoelectric element 206 and the drive IC (not shown) are electrically connected since the drive IC is mounted on this FPC 210.
Further, there are methods where an electrode terminal on a mounting substrate on which the IC drive is mounted and an electrode terminal provided on the exterior surface of the recording head are connected with a wire-bonding method (see, for example, the Official Gazette of Japanese Patent Application Laid-Open (JP-A) No. 2-301445). Furthermore, there are systems where after joining and connecting a drive IC to an electrode terminal provided on the exterior surface of the recording head, an FPC is joined and connected to an electrode terminal of pullout wiring provided on the recording head (see, for example, the Official Gazette of JP-A No. 9-323414).
Nevertheless, in both of these cases, when the nozzles are set in a highly dense arrangement, the sizes of the mounting substrate and FPC increase since wiring of a minute pitch (e.g., a pitch of 10 μm or less) cannot be formed. This causes problems such as inhibiting the compactness of the device and increasing the cost. Further, when the density of the nozzles arrangement becomes high, wiring having the desired resistance value cannot be drawn out, so there have been limitations to how densely the nozzles can be arranged due to limitations on the wiring density.